Attentive viewers may recall that, a few years back, Neanderthals made headlines again for the first time in 40,000 years. In 2010, advanced DNA testing confirmed that many modern humans have bits of Neanderthal DNA, suggesting the the two groups hooked up in Eurasia back in the day. As Natalia Reagan reports in today's DNews dispatch, Neanderthals weren't the only other archaic human group we fooled around with.

Scientists have recently confirmed, through DNA testing, that homo sapiens admixed with at least two other ancient offshoots of human development. Genetic traces of the extinct species known as Denisovans have been found in modern Southeast Asians and Australasians. And now scientists think they've found a fourth mystery group in our collective DNA, suggesting that we've been getting our freak on, as a species, for a long time. Natalia has the details.